Nut

ABSTRACT

An outer body of a nut defines an axial port and carries initial guide means. An inner body, movably accepted in the port in the axial direction, is divided into at least two jaws in the axial direction, which carry respectively an internal thread segment on their inner radial area. The jaws also include second guide means which interact with the first guide means in such a way that the jaws, when the outer body is moved relative to the inner body in a loosening direction, are moved radially outwards, and if the outer body is moved relative to the inner body in a tightening direction, are moved radially inwards. As the jaws can be moved when movement is in the radial direction, their internal thread segments can be brought smoothly into engagement with the outer thread of a threaded rod.

RELATED APPLICATIONS

[0001] This application claims the benefit of PCT InternationalApplication Serial No. PCT/DE01/01838, filed May 16, 2001 which claimsthe benefits of German Utility Model Application Serial No. 100 23675.8, filed May 16, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates in general to a fast mounting nut.

[0004] 1. Description of the Related Art

[0005] A type of fast mounting nut is known from DE 40 24 784 A1. Withthis known nut an axial port of an outer body, which is describedtherein as an outside member, is a hexagonal inner borehole with aforemost region, which has constant internal dimensions in the axialdirection, as well as an attaching conical region, which approaches theaxis in the loosening direction of the nut.

[0006] The jaws of this known nut, which is described therein asinternal nut segments, have respectively a front section which bears therespective internal thread segment, and a rearward section connecting inone piece to it. This rearward section is shaped similar to the frontsection, but relative to this is bent slightly outwards and, instead ofthe internal thread segment, has a threadless recess whose internaldimensions are larger than the internal thread segment.

[0007] The jaws are pivotally supported on one another at the transitionpoint between the front section and the rearward section. If the outerbody is now moved forward relative to the inner body, in other words inthe tightening direction of the nut, then the jaws are swivelled towardsone another in such a way that the front sections fold up, are closed inother words, so that the internal thread segments in the front sectionsform the internal thread of the nut. In this closed state of the nut theouter body sits on the front sections, whilst the rearward sectionsswing open.

[0008] If, on the other hand, the outer body is moved rearward relativeto the inner body, in other words in the loosening direction of the nut,onto the opened, rearward sections, then the jaws are swivelled towardone another in such a way that the rearward sections are folded up, sothat the front sections, which are of course connected in one piece tothe rearward sections, are taken along and opened. In this opened stateof the nut the internal thread is thus expanded, as the internal threadsegments are opened, so that these no longer engage with a threaded rodwhich is guided through the nut. Furthermore, the recesses in therearward sections now form a cavity through which such a threaded rodcan be pushed.

[0009] A similar nut is known from FR 2 640 336 A1. Even with this nutthe jaws are pivotally supported on one another, although with this nutthe rearward sections bear the internal thread segments, whilst thefront sections have the threadless recess. This nut is therefore closedwhen the outer body is moved in the loosening direction relative to theinner body, and opened, when the outer body is moved relative to theinner body in the tightening direction.

[0010] Both the known nut in accordance with DE 40 24 784 A1 and theknown nut in accordance with FR 2 640 336 A1 have, on the one hand, theadvantage that the inner body is clearly longer than the inner thread,as the sections with the threadless recess connect respectively and inone piece with the sections which bear the internal thread segments.These latter sections with the threadless recess cannot be dispensedwith, however, as they are required to open the sections with internalthread segment. The known nuts are therefore necessarily longer thantheir internal thread.

[0011] The known nuts have, on the other hand, the disadvantage that itis relatively difficult, to open and close the jaws, when the screw sitson a threaded rod. This is because each internal thread segment relativeto the outer thread of the threaded rod is rotated around an axis duringthe folding movement, this axis being located at right angles to thelongitudinal axis, so that the threads interlock easily.

[0012] Hence, those skilled in the art have recognized a need a fastmounting nut which is shorter for the same length of the internal threadand which can be opened and closed more easily. The invention fulfillsthese needs and others.

SUMMARY OF THE INVENTION

[0013] Briefly, and in general terms, the invention is directed to a nuthaving an outer body which defines an axial port and carries initialguide means. The nut also includes an inner body, that is movablyaccepted in the port in the axial direction. The inner body is dividedinto at least two jaws in the axial direction, which carry respectivelyan internal thread segment on their inner radial area. The jaws alsoinclude second guide means which interact with the first guide means insuch a way that the jaws, when the outer body is moved relative to theinner body in a loosening direction, are moved radially outwards, and ifthe outer body is moved relative to the inner body in a tighteningdirection, are moved radially inwards. As the jaws can be moved whenmovement is in the radial direction, their internal thread segments canbe brought smoothly into engagement with the outer thread of a threadedrod.

[0014] As, with this nut, the jaws are moved in a radial direction whenthey are opened and closed, their internal thread segments can bebrought smoothly into engagement with the outer thread of a threaded rodand can be just as easily moved away from this again. Moreover, as thejaws do not require any sections which have a thread-free recess, theirlength need only correspond to the desired length of the internalthread. This nut in the closed state is therefore not longer than aconventional one-piece nut.

[0015] Further features and embodiments of the invention are describedin the sub-claims. For example, it can be provided that the second guidemeans comprise grooves which run in the lateral areas of the jaws anddetach themselves from the axis in the tightening direction and that thefirst guide means comprise noses, which project from the port and run inthe grooves. As the grooves in the tightening direction detachthemselves from the axis, the jaws are moved radially inward, when theouter body in the tightening direction is pushed onto the inner body,and pushed radially outwards, when the outer body in the looseningdirection is pulled away from the inner body.

[0016] An outer wedge surface can also be provided on each jaw, whichwedge surface detaches itself in the tightening direction from the axis,and on the port for each jaw an inner wedge surface is provided whichmoves away from the axis in the direction of tightening andcorresponding to the assigned outer wedge surface. The jaws can also bepre-stressed radially outwards.

[0017] A locking pin can also be provided, which is movably guideddiagonally to the axis through the outer body and in its lockingposition with its inner end abuts a locking surface, which is providedon at least one jaw diagonally to the axis in the tightening direction,and in its release position can be moved with its inner end past thislocking surface and together with the outer body in the looseningdirection.

[0018] In one configuration the outer end of the locking pin in thelocking position projects from the outer peripheral surface of the outerbody and the inner end of the locking pin and the locking surface areformed so that the locking pin can be brought out of the lockingposition into the release position by pressing in. A further preferredprovision is for the locking pin to be pre-stressed in the lockingposition.

[0019] These and other aspects and advantages of the invention willbecome apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a cut lateral view of a nut in an initial embodimentwith the jaws opened;

[0021]FIG. 2 is a cross-section along the line II-II in FIG. 1;

[0022]FIG. 3 shows the nut from FIG. 1 with the jaws closed;

[0023]FIG. 4 is a cross-section along line IV-IV in FIG. 3;

[0024]FIG. 5 is a lateral view of a jaw in the initial embodiment forthe nut in FIGS. 1 to 4;

[0025]FIG. 6 is a lateral view of two jaws in a second embodiment;

[0026]FIG. 7 is a front view of FIG. 6;

[0027]FIG. 8 is a cross-section through a nut with jaws in a thirdembodiment;

[0028]FIG. 9 is a cut lateral view of a nut in a second embodiment withthe jaws opened;

[0029]FIG. 10 shows the nut from FIG. 9 with the jaws closed;

[0030]FIG. 11 is a cut lateral view of a nut in a third embodiment withthe jaws opened;

[0031]FIG. 12 shows the nut from FIG. 11 with the jaws closed;

[0032]FIG. 13 is a cut lateral view of a nut in a fourth embodiment;

[0033]FIG. 14 is a cross-section through a nut in a fifth embodiment;

[0034]FIG. 15 is a cross-section through a nut with a locking device inan initial embodiment;

[0035]FIG. 16 is a cut plan view of a nut with a locking device in asecond embodiment;

[0036]FIG. 17 is a cut lateral view of a nut in a sixth embodiment; and

[0037]FIG. 18 is a cut lateral view of a nut in a seventh embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] FIGS. 1 to 4 show a nut in an initial embodiment. In accordancewith FIGS. 1 and 2 the nut 10 is in an opened state, i.e., with nothread engagement, so that it may be move along the threaded shaft 12 ofa screw guided through two items 14 to be screwed together. The nut maybe pushed in either a tightening direction toward the two items 14 (tothe left in FIG. 1) or a loosening direction away from the two items 14(to the right in FIG. 1).

[0039] The nut 10 has an outer body 16 and two jaws 18, 20. The outerbody 16 has an axial port 22, in which the jaws 18, 20 are movablyaccepted in the axial direction, as described in detail below. The port22 here has a square cross-section and runs coaxially to thelongitudinal axis A of the nut 10. Here, the jaws 18, 20 aresquare-shaped blocks, whose length corresponds to the length of theouter body 16 and whose width is slightly less than the width of theport 22, as can be seen in FIG. 2, so that they sit so they do not twistin the port 22. Each jaw 18, 20 has on its radially inner surface, i.e.,the surface which faces the threaded shaft 12, an internal threadsegment which is formed so that it fits the outer thread of the threadedshaft 12. As a result, the upper jaw 18 shown in FIGS. 1 and 2 has itsinternal thread segment 24 on its underside, whereas the lower jaw 20bears its internal thread segment 24 on its upper side.

[0040] As can be seen in FIG. 2, the two jaws 18, 20 are distributedsymmetrically around the longitudinal axis A and therefore also aroundthe threaded shaft 12, so that they are at an angular distance of 180°to one another. This arrangement also applies accordingly to otherembodiments (not shown) of the nut 10, more than two jaws being providedin these cases. In the case of three jaws these are then preferablyarranged at an angular distance of 120° to one another around thelongitudinal axis A.

[0041] With reference to FIG. 2, initial guide means are provided on theouter body 16, which comprises four noses 26 which project from the port22. Here two noses 26 are arranged respectively on the left hand sideand on the right hand side of the port 22 at the same distance above andbelow the longitudinal axis A. The noses 26 are formed by the inner endof pins which are pushed into ports 28 in the outer body 16 from theoutside.

[0042] Matching these initial guide means on the outer body 16 are twoguide means provided on the jaws 18, 20 as shown in FIGS. 1, 2 and 5.The guide means comprise four grooves 30, in which one of the noses 26runs respectively. Each jaw 18, 20 has on its left-hand lateral surfaceshown in FIG. 2 a groove 30 and another groove 30 symmetrical to this inits right-hand lateral surface. Each groove 30 distances itself here asshown in FIGS. 1 and 5 in the tightening direction from the longitudinalaxis A, so that its distance to the longitudinal axis A in FIG. 1 isgreater on the left hand side than on the right hand side. Each groove30 therefore runs essentially axially in a plane parallel to and at adistance from the longitudinal axis A. Although the grooves are straighthere, they may also be bent in an axial direction.

[0043] The method of operation of the nut 10 is described in thefollowing with reference to FIGS. 1 to 4. In FIGS. 1 and 2 the nut isshown in the opened state, in which the jaws, 18, 20 are spaced so farapart, that their internal thread segments 24 do not engage with theouter thread of the threaded shaft 12. The nut 10 in this opened statecan therefore be drawn quickly to the right in FIG. 1, in the looseningdirection in other words, off the threaded shaft 12, without it havingto be rotated around its longitudinal axis A, as is the case with aconventional, one-piece nut. The nut 10 can also be pushed to the left,in the tightening direction in other words, onto the threaded shaft 12quickly, without having to be rotated.

[0044] As can be seen clearly in FIG. 1, the outer body 16 is pushedrelative to the jaws 18, 20 in the direction of loosening as far as thestop of the noses 26 at the right hand end of the grooves 30, so thatthe jaws 18, 20 are only inserted approximately halfway into the port22. As each groove 30 is with its right hand end closer to thelongitudinal axis A than with its remaining course, the jaws 18, 20 aremoved apart so that their internal thread segments 24 do not engage withthe threaded shaft 12.

[0045] As the height of the jaws 18, 20 is selected so that with theirradially outer surface 32, which is its upper side in the case of theupper jaw 18 and in the case of the lower jaw 20 its underside, in thisopened state of the nut 10 abuts the upper respectively lower surface ofthe port 22, they are prevented from tipping downward around the noses30 and the left hand lower edge of the jaw 18 and the right hand upperedge of the lower jaw 20 abut the threaded shaft 12.

[0046] In order to close the nut 10 this is pushed out of the positionshown in FIG. 1 until the jaws 18, 20 push with their left hand facesurfaces against the items 14 to be connected. If the outer body 16 ispushed further to the left relative to the threaded shaft 12, it is nowalso pushed to the left relative to the jaws 18, 20 and therefore, asthis can no longer go round to the side, pushed onto it. As the outerbody 16 is now pushed relative to the jaws 18, 20 in the tighteningdirection, the noses 26 run in the grooves 30 in the tighteningdirection as well, so that the jaws 28, 20 are pushed radially inwardsand therefore closed. As the jaws 18, 20 are moved radially inwards, inother words towards the threaded shaft 12, the full length of theirinternal thread segments 24 engages evenly with the outer thread of thethreaded shaft 12. In this way the internal thread segments 24 areprevented from interlocking and jamming with the outer thread throughdiagonal seating of the jaws 18, 20 on the threaded shaft 12. Otherwisethere is the risk that the nut 10 cannot be fully closed or, if this isnevertheless achieved with excessive force, that the threads of thethreaded shaft 12 and/or of the jaws 18, 20 are damaged.

[0047] If the outer body 16 is pushed fully onto the jaw 18, 20, thenthe nut 10 is in the closed state as shown in FIGS. 3 and 4. As can beseen clearly in FIG. 3 the noses 26 then sit in the left hand end of thegrooves 30, so that the internal thread segments 24 together form onepart of an inner thread, which matches the outer thread of the threadedshaft 12, as can be seen clearly in FIG. 4. The jaws 18, 20 thereforetogether form an inner body, which is accepted so that it cannot twistin the port 22 and movably in an axial direction as required by a nut10. On the contrary it can be said that the inner body is divided intotwo jaws 18, 20 in an axial direction.

[0048] If the nut is in the closed state shown in FIGS. 3 and 4, it canbe tightened like a conventional, single-piece nut, as the inner body18, 20 sits so that it cannot twist in the port 22.

[0049] So that the outer body 16 does not slip accidentally relative tothe inner body in the loosening direction, which can occur, for example,if the screw connection of nut 10 and threaded shaft 12 is exposed tovibrations, the grooves 30 may have a section on their left hand endwhich section runs parallel to the longitudinal axis A only whenconnected to this parallel section in the loosening direction, in otherwords approaches the longitudinal axis A rightwards. This can be seenparticularly clearly in FIG. 5. In order to loosen the jaws 18, 20, theouter body 16 must therefore be pushed relative to these in theloosening direction, until the noses 26 arrive at the right hand of thisparallel section of the grooves. Only when the outer body 16 is thenpushed further in the loosening direction, do the noses 26 run in theoblique groove sections, so that the jaws 18, 20 are pushed radiallyoutwards. As a result, the engagement of the internal thread segments 24with the outer thread of the threaded shaft 12 continues to loosen untilthe outer body ultimately 16 is pushed relative to the inner body 18, 20in the loosening direction until the noses 26 strike at the right handend of the grooves 30. The nut 10 has then again assumed the openedstate, in which the jaws 18, 20 do not engage with the threaded shaft12, so that the nut 10 can be quickly pulled away the threaded shaft 12again.

[0050] Two jaws 18, 20 are shown in a second embodiment in FIGS. 6 and7. Here and to the left next to each groove 30 a second groove 30′ isprovided. Accordingly, the outer body 16 to the left in FIGS. 1 to 4have next to each nose 26 (shown as a dotted line) a second nose 26′ aswell (shown as a dotted line), which runs in the second groove 30′. Thiscauses the jaws 18, 20 to be held as parallel as possible to thelongitudinal axis A.

[0051] Also provided in this second embodiment are means which preventthe jaws 18, 20 from being moved axially relative to one another, if theouter body is pushed onto them or pulled away from them. Such means arealso suitable for all other embodiments of the jaws. These meanscomprise here, for example, two guide roads 110 which are arranged onthe right hand end of the jaws 18, 20 in FIGS. 6 and 7 to the left andright next to the longitudinal axis A and seat respectively movably intwo opposing guide boreholes 112 in the jaws 18, 20. The jaws 18, 20 cantherefore for opening and closing as desired be moved radially relativeto one another but not axially. The means may also comprise fewer ormore than two guide rods 110.

[0052] Furthermore, the jaws 18, 20 are pre-stressed radially outwardsby two helical springs 114 which respectively comprise a guide rod 110and are supported on the underside of the lower jaw 18 and on the upperside of the lower jaw 20. As a result, the opening of the jaws 18, 20 issupported when the outer body 16 is pulled away.

[0053] In contrast to the form of the jaws 18, 20 shown in FIGS. 1 to 7these may of course also be formed so that they form a complete innerthread when closed, as shown in the third embodiment of the jaws 18, 20in accordance with FIG. 8.

[0054] The nut 10 is shown in a second embodiment in FIGS. 9 and 10. Incontrast to the first embodiment of FIGS. 1 to 5, wedge surfaces 34, 36are provided in addition corresponding to the first and second guidemeans 26, 30.

[0055] On the one hand an inner wedge surface 34 is provided for eachjaw 18, 20 which surface is formed by the port 22 and moves away fromthe longitudinal axis A in the tightening direction. Inner wedge surface34 is formed on the upper side of the port 22 pointing down and facingthe upper jaw 18, and a second inner wedge surface 34 is formedsymmetrically to this on the underside of the port 22 pointing up facingthe lower jaw 20.

[0056] On the other hand an outer wedge surface 36 is provided on eachjaw 18, 20, which surface is formed corresponding to the respectiveopposite inner wedge surface 34 and so moves away from the longitudinalaxis A in the tightening direction. An initial outer wedge surface 36 isformed on the upper side of the upper jaw 18, and a second outer wedgesurface 36 is formed symmetrically to this on the underside of the lowerjaw 20.

[0057] The corresponding inner and outer wedge surfaces 34, 36 areformed in such a way that, when the nut 10 is closed, they match eachother exactly, as can be seen clearly in FIG. 9, and their obliqueposition relative to the longitudinal axis A is in terms of the obliqueposition of the grooves 30 such that they can be moved past each otherwhen the outer body 17 is moved relative to the inner body 18, 20 foropening and closing the nut 10. When the nut 10 is closed, frictionlocking therefore occurs between the inner and outer wedge surfaces 34,36 so that the outer body 16 is held on the inner body 18, 20.

[0058] In FIGS. 11 and 12 the nut 10 is shown in a third embodimentwhich represents a modification of the second embodiment of FIGS. 9 and10. Here, the wedge surfaces 36, 36 are sub-divided into five sections,namely into three section 120 parallel to the longitudinal axis A andtwo oblique sections 122 which move away from the longitudinal axis A inthe tightening direction and are located between the three parallelsections 120. Fewer or more than three parallel sections 120 and/orfewer or more than two oblique sections 122 can also be provided. Thegrooves 30 run correspondingly parallel to the central parallel section120 and the right-hand, oblique section 122 connecting to it to theright.

[0059] In the closed state of FIG. 12 the outer wedge surface 36 abutswith its parallel sections 120 the corresponding, parallel sections 120of the inner wedge surface 34, whilst with its oblique sections 122 itmay optionally abut the corresponding oblique sections 122 of the innerwedge surface 34 as shown in FIG. 12 or may also be at a distance tothese. The sections 120 lying parallel to one another absorb the forcesdirected radially outwards and which, when the nut 10 is closed, aretransmitted from the outer thread of the threaded shaft 12 via theinternal thread segments 24 to the jaws 18, 20. As these parallel 120sections lie at right angles to these radial forces, only one radialcomponent is transmitted to the outer body 16, but not an axialcomponent directed in the loosening direction, as is the case with theoblique wedge surfaces 34, 36 of the second embodiment. However, thisaxial component may, if it is of sufficient magnitude, lead to the outerbody 16 slipping away relative to the inner body 18, 20, accidentallycausing the nut 10 to loosen. This is prevented therefore by theparallel sections 120.

[0060] Although the wedge surfaces 34, 36 shown in FIGS. 9 to 12 areflat here, they may also be bent as desired in an axial direction and/orin a peripheral direction.

[0061] In accordance with FIGS. 11 and 12 a flange 124 projectingradially outwards is provided on the left-hand outer edge of the jaws18, 20 such that when the nut 10 is closed a gap is formed between theright-hand edge of the edge and the left-hand face surfaces of the outerbody 16. The blade of a screwdriver can be placed in this gap, forexample, and turned, in order to lift the nut 10 if the outer body 16 isso firmly seated on the inner body 18, 20 that it cannot be pulled awayusing the fingers. This flange 124 is also suitable for all otherembodiments of the nut 10.

[0062] The aforementioned, accidental slipping of the outer body 16relative to the inner body 18, 20 in the loosening direction can also beprevented or at least rendered more difficult by the following measuresshown in FIGS. 13 to 16.

[0063] For example, therefore, and in accordance with FIG. 13 in whichthe nut 10 of FIGS. 9 and 10 is shown in a modified, fourth embodiment,a clamping body 38 can be fitted on the right-hand end of the innerwedge surface 34 and/or on the left-hand end of the outer wedge surface36, which clamping body projects from the corresponding wedge surface34, 36 and which is made from a ductile material such as rubber orsilicone. If the outer body 16 is pushed out of the position shown inFIG. 13 relative to the jaws 18, 20 and further to the left, theleft-hand end of the inner wedge surface 34 and the right-hand end ofthe outer wedge surface 36 are forced under the right-hand clamping body38, so that the clamping bodies 38 are distorted and increase thefriction between the inner and outer wedge surfaces 34, 36. Theleft-hand edge of the inner wedge surface 34 and the right-hand edge ofthe outer wedge surface 36 are preferably chamfered in doing so, inorder to be able to push these wedge surfaces 34, 38 more easily intothe clamping bodies 38.

[0064] In accordance with FIG. 14, in which the nut is shown in a fifthembodiment, clamping bodies 38 may also be fitted to the upper jaw 18and/or the lower jaw 20, which are nipped between these jaws 18, 20 whenthe nut 10 is closed. As a result the jaws 18, 20 are pressed radiallyoutwards, so that in the case of the second embodiment of FIGS. 9 and 10and the third embodiment in FIGS. 11 and 12 the friction is increasedbetween the inner and outer wedge surface 34, 36 and in the case of thefirst embodiment of FIGS. 1 to 4 the friction is increased between thenoses 26 and the radially outer surfaces of the grooves 30.

[0065] In FIGS. 15 and 16 the nut 10 of FIG. 4 is shown with a lockingdevice which prevents the outer body 16 from being capable of beingmoved relative to the inner body 18, 20 in the loosening direction whenthe nut 10 is closed.

[0066] The locking device in an initial embodiment in accordance withFIG. 15 has a locking pin 40 which is movably guided transversely to thelongitudinal axis A in a through-hole by the outer body 16 and projectswith its inner end from the through-hole 22. A locking surface 42 isalso provided on the upper jaw 18 which surface points transversely tothe longitudinal axis A in the tightening direction. This lockingsurface 42 is here part of a projection which projects downward at theleft-hand edge of the lower side of the upper jaw 18 and ends above theupper side of the locking pin 40. The inner end of the locking pin 40bears an extension 44 bent upwards which abuts the locking surface 42when the locking pin is in the locked position. If the locking pin 40 isnow pushed out of the position shown in FIG. 15 radially inwards intoits release position, the extension 44 is also moved radially inwardsuntil it lies next to the locking surface 42 to the right in FIG. 15 andso can be pushed inside past this surface and together with the outerbody 16 into the loosening direction.

[0067] The locking pin 40 is pre-stressed radially outwards by a helicalspring 46, in other words into the locking position, which surrounds athinner central section of the locking pin 40 and together with thelocking pin 40 sits in the through-hole. The helical spring 46 issupported by its radial, inner end on a shoulder of a through-hole andby its radial, outer end on a shoulder of the locking pin 40, as can beclearly seen in FIG. 15.

[0068]FIG. 16 shows the locking device in a second embodiment. With thissecond embodiment the upper jaw 18 has a recess 48 at the right-hand endof its lateral surface pointing upwards in FIG. 16 and which accepts anL-shaped spring plate 50. The axial side of this spring plate 50 issecured in the right-hand wall of the recess 48, and the radial side ofthe spring plate 50 is directed outwards and projects in the relaxedstate of the spring plate 50 from the lateral surface of the jaw 28. Inthe closed state shown in FIG. 16 of the nut 10 the free end of thisradial side projects into a through-hole 52 in the outer body 16. Inthis locking position as a result the outer body 18 is prevented frommoving relative to the jaw 18 in the loosening direction, in other wordsto the right in FIG. 16. The left-hand edge of the through-hole 52 thencomes into contact with the radial side and pushes this still deeperinto the through-hole 52, bending the axial side radially upwards. Thisleft-hand edge of the through-hole 52 therefore has the same function asthe locking surface 42 of the first embodiment of the locking device.

[0069] In order to bring the spring plate 50 into the release position,a release pin 54 is arranged in the through-hole which, like the lockingpin 40 in FIG. 15, is pre-stressed radially outwards by a helical spirng46 and projects with its outer end from the outer body 16. If therelease pin 54 is now pressed radially inwards, its inner end thenpushes the radial side of the spring plate 50 out of the through-hole52, the axial side bending elastically and radially inwards. As soon asthe radial side no longer projects into the through-hole 52 the outerbody 16 can be pushed into the loosening direction.

[0070] A blind hole 56 is provided in the outer body 16 further to theleft next to the through-hole 52 and into which the radial side engageswhen the outer body 16 is pushed in the loosening direction until theinternal thread segments 24 no longer engage with the outer thread ofthe threaded shaft 12. If the nut 10 is pushed in this opened state inthe tightening direction onto the threaded shaft 12, then the radialside engaged in the blind hole 56 prevents the outer body 10 from beingpushed onto the inner body 18, 20, if an internal thread segment 24 isaccidentally caught on the threaded shaft 12.

[0071] If, finally, the nut 10 cannot be pushed any further in thetightening direction onto the threaded shaft 12, because the inner body18, 20 is with its left-hand face surface striking the items 14 (FIG. 3)to be screwed together, then the radial side is pressed out of the blindhole 56. In order to facilitate this, the right-hand wall of the blindhole 56 is tilted downwards and to the right in accordance with FIG. 16.

[0072] With this second embodiment of the locking device the release pin54 can also be dispensed with. In order then to be able to bring theradial side engaged in the through-hole 52 into the release position,the left-hand wall of the through-hole 52 can then be tilted downwardand to the left (not shown), as described for blind hole 54. If theouter body 16 is now pulled into the loosening direction with sufficientforce, the radial side abutting the tilted wall is turned radiallyinwards until it no longer projects into the through-hole 52 and theouter body 16 can continue to be pulled away unhindered relative to theinner body 18, 20.

[0073] Each locking device in FIGS. 15 and 16 is not only suitable fornuts 19 with radially movable jaws 18, 20, as they are the object ofthis invention, but also for the known nuts with swivelling jaws as theyare described, for example in DE 40 24 784 A1 and FR 2 640 336 A1. Thisalso applies to the clamping bodies in FIGS. 13 and 14.

[0074] Both the locking pin 40 in FIG. 15 and the release pin 54 in FIG.16 project in their locking position with their outer end from the outerbody 16, so that the user can push them in with one finger forloosening. However, in order to prevent them from being accidentallypushed in, these outer ends may in the locking position also liecountersunk in the corresponding through-hole. For loosening a tool isthen required, pincers for example, with a tooth which fits in thethrough-hole and with which the locking pin 40 respectively the releasepin 54 can be pushed in.

[0075] The nut 10 in a sixth embodiment is shown in FIG. 17. With thisembodiment the jaws 18, 20 have a threadless recess 58 on theirright-hand end in connection with their internal thread segment 24 andin which a bent insert 60 made of ductile material such as plastic sits.When the jaws 18, 20 are closed the outer thread of the threaded shaft12 pushed into these inserts 60, achieving self-locking of the nut 10 inthe closed state to protect against accidental undoing.

[0076] The nut 10 is shown in FIG. 18 in a seventh embodiment. This nut10 is intended for use on flanged pipes 60 which bear a flared flange 64at their ends. With this seventh embodiment and similar to the sixthembodiment a recess 58 is provided at the right-hand end of the jaws 18,20 into which the nut 10 of the flared flange 64 fits in the closedstate. In the illustrated, closed state of the nut 10 the jaws 10, 20are moved apart from one another until the flared flange 64 can bepulled to the right in FIG. 18 and out of the recess 58. This isnecessary when, for example, nuts 10 seated on the flanged pipe 62 haveto be replaced.

[0077] It will be apparent from the foregoing that while particularforms of the invention have been illustrated and described, variousmodifications can be made without departing from the spirit and scope ofthe invention. Accordingly, it is not intended that the invention belimited, except as by the appended claims.

What is claimed is:
 1. A nut comprising: an outer body which has anaxial port; and inner body, which is movably accepted in the port in anaxial direction, has an axial internal thread and is divided into atleast two jaws in an axial direction, which jaws bear an internal threadsegment on their radially inner surface and which, when the outer bodyis moved relative to the inner body in the loosening direction of thenut are moved apart; initial guide means provided on the outer body; andsecond guide means provided on the jaws and interact with the initialguide means such that the jaws are closed, when the outer body is movedrelative to the inner body in the loosening direction of the nut,characterized in that: the second guide means interact with the initialguide means such that the jaws when the outer body is moved relative tothe inner body in the loosening direction, are pushed radially outwardsand, when the outer body is moved in the tightening direction relativeto the inner body, are pushed radially inwards.
 2. The nut of claim 1characterized in that the second guide means comprise grooves, which runin the lateral surfaces of the jaws and move away from the axis in thetightening direction, and in that the initial guide means comprisenoses, which project from the port and run in the grooves.
 3. The nut ofclaim 1 characterized in that on each jaw an outer wedge surface, whichmoves away from the axis in the tightening direction, and at the portfor each jaw an inner wedge surface is provided, which, corresponding tothe assigned, outer wedge surface moves away from the axis in thetightening direction.
 4. The nut of claim 1 characterized in that thejaws are pre-stressed radially outwards.
 5. The nut of claim 1characterized in that a locking pin is movably guided transversely tothe axis through the outer body and in its locking position with itsinner end abuts a locking surface, which is provided at at least one jawtransversely to the axis pointing in the tightening direction, and inits release position can be moved with its inner end past this lockingsurface and together with the outer body in the loosening direction. 6.The nut of claim 5 characterized in that the outer end of the lockingpin in the locking position projects from the outer peripheral surfaceof the outer body and the inner end of the locking pin and the lockingsurface are formed such that the locking pin can be brought out of thelocking position into the release position by pressing in.
 7. The nut ofclaim 5 characterized in that the locking pin is pre-stressed into thelocking position.